This invention relates to a data network, particularly to a sensor network capable of reasonably managing energy consumption.
The possible application environments of sensor networks are very extensive, such as physiological monitoring, environmental monitoring (air, water, soil, etc.), condition-triggered maintenance, intelligent space, military uses, stock management, and other work unsuitable for human beings to do.
A sensor network generally comprises a set or sets of sensors (also referred to as nodes in a sensor network) connected by wire or wireless means for jointly or separately doing specific work. Each sensor of the sensor network normally has one or more of the following functions: inducing, storing, transmitting, relaying, accepting query, triggering events, and processing data, etc.
Since sensors of the sensor network are small, inexpensive, easy to be disposed and increasingly strong in function, the sensor network becomes more and more popular. But, with these special characteristics mentioned above, the energy use and storage of sensors have increasingly become an important problem. How to maximize the working time of sensors without affecting the efficiency of sensors and sensor networks has become a topic of heated discussion.
The US patent application (Pub. No. US 2003/0063585A1; applicant: the US Honeywell Inc.; and inventor Mohamed F. Younis) has disclosed a method for managing energy consumption of sensor network. Firstly, dividing the sensors of the sensor network into plurality of groups according to a specific rule, and each group has a sensor acting as a gateway for transmitting data of each sensor to a control node. Then, setting up a route table for each group in a corresponding gateway, and setting up a relatively smaller rout table at each sensor node, so as to consume minimum energy. After that, monitoring the available energy of each sensor. Finally, re-setting up the route table according to the variation of the available energy of each sensor.
The US patent application has reduced, to a certain extent, energy consumption of each group of sensors. However, each group of sensors has a sensor used as a gateway for coordinating the work of all the sensors in the group, if the gateway is damaged (it is quite possible for it to be damaged under some adverse circumstances), it would greatly affect the efficiency of the group and even the entire sensor network. Further, since the gateway serves as the core of the entire group of sensors, all the sensors need to communicate with the gateway to finish the work, which would inevitably increase the quantity of communication within the group, and, thus, increase the energy consumption of the group, particularly increase the energy consumption of some relay nodes.
Therefore, both a new sensor network and a new method for managing energy consumption in a sensor network are needed, so as to make it possible for the sensor network to maximize the life of sensors without affecting the efficiency of the sensors and the sensor network.